1. Field of the invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for reporting a logged measurement in a wireless communication system.
2. Related Art
3rd generation partnership project (3GPP) long term evolution (LTE) is an improved version of a universal mobile telecommunication system (UMTS) and is introduced as the 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink, and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink The 3GPP LTE employs multiple input multiple output (MIMO) having up to four antennas. In recent years, there is an ongoing discussion on 3GPP LTE-advanced (LTE-A) that is an evolution of the 3GPP LTE.
Minimization of driving tests (MDT) is a test performed by service providers for coverage optimization by using a user equipment (UE) instead of using an automobile. A coverage varies depending on a location of a base station (BS), deployment of buildings nearby, a user's usage environment, etc. Therefore, it is required for the service providers to periodically perform the driving test, and a lot of costs and resources are consumed. The MDT is used when the service provider measures the coverage by using the UE.
The MDT can be classified into a logged MDT and an immediate MDT. According to the logged MDT, after performing the MDT measurement, the UE delivers a logged measurement to a network available at a time of a reporting condition. According to the immediate MDT, after performing the MDT measurement, the UE delivers the measurement to the network at points in time when a configured reporting condition is satisfied. The logged MDT performs the MDT measurement in a radio resource control (RRC) idle mode, but the immediate MDT performs the MDT measurement in an RRC connected mode.
When the BS requests the UE to report a logged measurement, the UE transmits one report message in general. However, a maximum size of message that can be transmitted at once is fixed. For example, a maximum size of a packet data convergence protocol (PDCP) service data unit (SDU) is 8188 bytes.
A method for dealing with a case where a size of a logged measurement exceeds a size of one message has not been introduced yet.